5|25: Celebrating Five Years of Autism Science Day 10: Functional Underconnectivity Theory of Autism

In honor of the anniversary of Autism Speaks’ founding on Feb 25, for the next 25 days we will be sharing stories about the many significant scientific advances that have occurred during our first five years together. Our 10th item, Functional Underconnectivity Theory of Autism, is from Autism Speaks’ Top 10 Autism Research Events of 2007.

Studies from several labs in the past few years have hinted that the deficits in autism may not be found in any single structure of the brain, but rather in wiring of the neural networks that connect the different parts of our brain together. This has lead to a theory of autism called “functional underconnectivity,” which hypothesizes that brain regions are not properly linked to each other, causing them to be functionally out-of-synch.

Scientists managed to directly test this hypothesis in 2007 by recording in real time the electrical signals that travel from one part of the brain to another. University of Washington researchers were the first to use a technique called “EEG coherence” to demonstrate underconnectivity in the brains of individuals with autism, finding that brain regions that were far apart did not “talk” to each other as typical. A collaborative team from the University of Colorado and the University of California at Davis also listened in on the brain activity of individuals with autism using a second technique called “MEG.” It appeared as if the brain regions that should normally be synchronized with each other were not, and that the front of the brain may be especially disconnected with other brain regions.

Our most complex cognitive and executive functions, such as perception, attention, and learning and memory, require the coordinated function of brain activity. In order to conceive targeted therapies that overcome deficits in these areas, we need to first understand the biological problems that are generating them. These studies added critical evidence that communication problems between regions of the brain may be central to the impairments in autism, and could be directing us toward the ultimate design of strategies to re-synchronize brain activity.

Did you know?: Most recently the functional underconnectivity hypothesis has been bolstered by insights from using one of the newest techniques that measures brain connectivity, known as “resting state” imaging. Autism Speaks awarded two grants at the end of 2008 to investigators from the University of Washington and New York University Medical School in order to apply this new technology to understand how differences in brain connectivity relate to ASD symptoms. [For more information, please read: http://www.autismspeaks.org/science/science_news/hrhi_funds_brain_connectivity_study.php]